1. Field of the Invention
The present invention concerns generally a post puller. In particular, the present invention is directed to an apparatus for efficiently clutching and extracting posts embedded in the ground, especially round metal posts which are often difficult to hold firmly during extraction, the post pulling apparatus functioning without having to pass the clutching mechanism over the free end of the posts, such posts including T cross-section posts, rectangular posts and round posts of differing diameters.
2. Description of the Related Art
Whether of urban, suburban, or rural locale, there are numerous and continuing instances entailing the placement in the ground of fence posts, sign posts, and the like. Depending upon the situation and economics, the cross-section of such posts and poles can include T-section, rectangular, square, and round; the material can be, wood, metal, or plastic. A frequent corollary to this ageless process is the need for subsequent extraction of those embedded posts and poles. As a consequence of this continuing problem, many devices have been devised and invented to expedite the extraction process. Development of such devices has had to confront numerous problems, including; slippage of the clutching mechanism holding the post; clutching mechanisms that need to be placed over the free end of the post; excessive preparation or setup required prior to extracting the post; excessive damage to the post during removal.
Perusal of patents issued during the past 35 years reveal an interest focused on a carriage featuring both a means for transporting the extraction apparatus to the job site and also means for providing an upward force to extract the post. With certain exceptions, clutching, that is, gripping or a holding tightly or firmly, the object to be extracted was given lesser attention.
Generally loose chain was wrapped around the object to be extracted. An adequate clutching force was sought by multiple encirclement of the post by the chain. For larger diameter wooden poles, a chain snubbing and pole gripping device could be physically attached to the pole and used in conjunction with a loose chain wrapped around the pole. U.S. Pat. No. 3,734,463 “CHAIN SNUBBING AND POLE GRIPPING DEVICE FOR POLE RAISING APPARATUS” is incorporated herein by reference for purposes of indicating the background of the present invention or illustrating the mature state of the art for clutching and extracting large diameter wooden poles.
Loose chain wrapped around a post was also used for smaller diameter posts embedded in the ground. Some of these devices utilizing loose chain have been mounted on carriages for ease and convenience in moving the device on the ground, and additionally incorporating a mechanism for applying an upward force to the post extraction effort. U.S. Pat. No. 6,302,377 “POST PULLING APPARATUS” is incorporated herein by reference for purposes of indicating the background of the present invention or illustrating the mature state of the art for the use of loose chain to clutch a small diameter post to be removed.
Loose chain has been known to slip when utilized to clutch a metal pole. Various pole and post clutching mechanisms have been devised and invented in an attempt to overcome and solve this problem. In some instances, the gripping mechanism, such as a fixed metal collar, must be passed over the free end of the post. In other cases, two opposing rigid surfaces act together to grip or clamp the post to be removed. U.S. Pat. No. 5,161,781 “TOOL ASSEMBLY FOR USE IN PULLING FENCE POSTS” is incorporated herein by reference for purposes of indicating the background of the present invention or illustrating the mature state of the art for utilizing an unsymmetrical gripping mechanism that additionally does not need to be passed over the free and the post.
In like manner, a symmetrical gripping mechanism can be utilized to clutch the post. U.S. Pat. No. 7,059,587 “POST PULLER” is incorporated herein by reference for purposes of indicating the background of the present invention or illustrating the mature state of the art for utilizing a symmetrical clutching mechanism that does need to be passed over the free end of the post.
Since the gripping surfaces of such devices are rigid, the gripping surface is largely dependent upon the diameter of the post. Consequently, if the diameter of the post is not particularly favorable, the gripping surface area may be too small and there is apt to be slippage of the post. The present invention provides a simple, efficient solution to the preceding deficiencies.